Temperature responsive fluid flow controllers

ABSTRACT

Controllers for regulating fluid flow, and especially flow of liquid in supply lines, each of which include a valve assembly which is slidably positioned in a bore extending transverse to a fluid passageway extending through the body of the controller. Each controller includes a shaped memory alloy spring which is mounted so as to be in heat exchange relationship with fluid flowing therethrough. Each spring is mounted adjacent a stem of a valve and is operable when heated to a predetermined activation temperature to shift the valve assembly to at least partially close the fluid passageway. In some embodiments, the valve assembly is manually operable at temperatures below the activation temperature to regulate flow through the controllers. In other embodiments, the valve assembly is automatically shifted to open the fluid passageway through the body of the controller when temperatures decrease below the activation temperature.

This application is a division of Ser. No. 08/664,545 filed Jun. 17,1996 now U.S. Pat. No. 5,803,354.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention is generally directed to fluid flow control valves and,more particularly, to valves which are responsive to the temperature offluids flowing in a passageway for automatically activating the valve toprevent or reduce fluid flow therethrough until the temperature of thefluid is below a predetermined activation temperature. The controllersof the present invention are particularly adaptable for liquid supplylines used for showers, bathtubs, sinks and the like, but also haveutility in other areas wherein it is necessary to control the flow of aliquid, or other fluid, to terminate or partially terminate flow in theevent the fluid temperature is above a predetermined temperature. In oneembodiment, the controllers are used to maintain a generally constanttemperature of a supplied fluid by functioning as a hot/cold fluidmixer.

2. History of the Related Art

There are many environments in which it is necessary to control the flowof hot gases or liquids to ensure industrial processing or to protectindividuals from injury due to exposure. By way of example, incommercial and residential hot water supply systems intended forpersonal use, water temperatures will frequently exceed 125° to 130° F.At these temperatures, an individual can easily become scalded or burnedby being in contact with the liquid in a matter of a few seconds. Therequirement to regulate the temperature becomes even more critical incommercial environments where a large source of hot water supply isnecessary during relatively short demand periods, such as in morning andevening hours. Often, temperatures are elevated in boilers or heaters ofa large system so that a sufficient source of hot water is available toa great number of users at a given time. Even in household environments,a hot water supply may be set to a regulated temperature in excess of130° F. for purposes of providing sufficiently hot temperatures fordishwashing and clothes washing. Under these circumstances, it iscritical to ensure that such hot water is properly mixed withsufficiently cold water before an individual bathes, showers or washes.

One of the problems inherent with regulating fluid supplies dependingupon temperature is the cost of a control system which can adequatelyfunction in a particular environment. Historically, the use ofelectronically controlled valves has not been satisfactory forcommercial and residential uses. However, through the development oftemperature sensitive metal alloys, it has been possible to createvalves which are mechanically actuated in response to the temperature offluids flowing through the valves.

Such mechanically operated valves incorporate spring elements made ofmetal alloys which are sensitive to temperature to vary the force of thesprings depending upon the ambient temperature to which they areexposed. Such springs are referred to as shaped memory alloys, whichexhibit a first biasing force regulated by their stiffness in amartensitic state, but which exhibit a greater force at elevatedtemperatures in their austenitic state. Therefore, such alloys can betreated so as to exhibit a transformation from a martensitic to anaustenitic state at predetermined temperatures so that springsconstructed therefrom automatically change their biasing force dependentupon temperature. Examples of valves incorporating shaped memory alloyspring elements are disclosed in U.S. Pat. Nos. 4,778,104 to Fisher,4,848,388 to Waldbusser, 5,259,554 to Ewing, et al. and 5,261,597 toPerlman, et al.

There remains a problem with the prior art valves which utilize shapedmemory alloy springs to automatically regulate flow of a gas or liquidthrough a supply line. Many valves are not constructed to operateconsistently within a preselected temperature range, especially if thepressure within a supply line varies. In most systems, the springelements are placed in line with the fluid flow through a valve and,therefore, the valve elements are subject to variations in fluidpressure created in either the opening or closing of the valves.Further, many prior art valves which provide for automatic control of avalve mechanism dependent upon the temperature of the fluid flowingtherethrough do not allow for a manual override or a manual resetting ofthe valves. There are many instances in which a manual override would bebeneficial for resetting a valve.

SUMMARY OF THE INVENTION

The present invention is directed to a temperature responsive fluid flowcontroller which may be utilized for regulating the flow ofsubstantially any fluid, liquid or gas, through a fluid supply line andwhich has particular utility as a temperature responsive flow controllerfor use in regulating the supply of hot water in both commercial andresidential environments. In many environments, the temperature of asource fluid, such as the hot water from a hot water heater, may bemaintained at a temperature in excess of a temperature at which it isdesired to supply the liquid to a showerhead, bathtub or sink faucet.

The controllers of the present invention include a housing which ispreferably formed of a molded plastic material having at least one inletand an outlet which are in communication through a flow passageway. Abore is provided through the housing in which a valve assembly isslidably received. The bore is oriented transverse to the flowpassageway and intersects therewith so that the valve assembly also istransverse to the flow passageway. The valve assembly includes a valvestem member having a base portion at one end thereof. In a firstembodiment, the base portion is separated from a portion of the stem byan annular slot which extends inwardly from the flow passageway ingenerally parallel relationship to the valve stem. A coil spring formedof a shaped memory alloy is mounted either within or about the valvestem so as to be at least partially in communication with the flowpassageway whereby fluid flowing through the passageway contacts thespring.

In a first embodiment, the spring is retained relative to the stem by acap member which is fitted to or secured with the outer portion of thestem. The cap has an inwardly extending skirt portion defining acylindrical bore in which the stem and surrounding spring arepositioned. Both the cap and the base portion of the valve stem areprovided with an outer sealing O-ring which are slidably engageableagainst the walls defining the bore through the controller housing. Toprevent the complete passage of the valve stem through the bore, thehousing has stop members which extend into the bore adjacent to the flowpassageway.

In a first position of the valve assembly, the flow passageway is openand the head portion of the valve stem is spaced from the fluidpassageway. In this open position, the spring is in its martensiticstate in a closely coiled configuration with one end abutting a portionof the valve assembly and the other end abutting a portion of thehousing. At a predetermined temperature between 110° and 135° F., thealloy from which the activating spring is constructed will transform toits austenitic state, expanding rapidly, thereby forcing the valveassembly to shift, urging the base portion into the flow passagewaywhere the base portion will substantially terminate flow through thepassageway.

In the preferred embodiment, the valve assembly will not close the fluidpassageway so that some fluid is allowed to pass through the controller.This will allow for pressure relief in the system and will continue toexpose the activating spring to temperatures within the supply system.

In some embodiments, the valve assembly may be manually opened bypushing the valve assembly in a direction opposite that of the force ofthe actuating spring so that the base portion of the valve stem isspaced from the fluid flow passageway. In the event fluid temperaturesremain too high, the valve will immediately close as the spring expands.However, if the fluid temperature has dropped below the predeterminedactivation temperature of the valve, the valve will remain in an openposition.

In another embodiment, a second spring is mounted within the bore so asto be in opposition with the first spring. The second spring exertssufficient force to overcome the force of the first spring as the firstspring changes state at lower temperatures to the martensitic state ofthe metal alloy.

In yet another embodiment of the present invention, the controller willfunction as a fluid mixer placed upstream of a control valve forsupplying fluids to an outlet such as a shower nozzle or faucet. In thisembodiment, the controller housing includes inlets for both hot and coldfluids, and a common outlet which are connected by a flow path whichextends through inlet and outlet openings on opposite sides of aslidable valve assembly which is mounted within a bore which extendstransversely with respect to the fluid flow passage. The valve assemblyis formed of a generally cylindrical valve stem having a pair of spacedinlet openings in one side wall thereof and which communicate witheither the hot or cold fluid inlets depending upon the position of thevalve assembly relative to the housing. At least one outlet opening isalso formed in the valve stem which communicates with the outlet of thehousing. One end or head of the cylindrical valve stem is sealed by anO-ring which is engageable with the inner walls of the housing spacedfrom the hot and cold fluid inlets.

Mounted within the cylindrical body of the valve stem is a shaped metalalloy spring of a type previously discussed. This spring engages aclosed end wall of the housing and the opposing head of the valve stem.When the valve assembly is in a first open position, fluid is allowed toenter into the mixer from only the hot fluid inlet opening. However, iftemperatures should exceed a predetermined activation temperature, theshaped metal alloy spring will change to its austenitic state, therebyexpanding against a second spring retained in a chamber positioned onthe opposite side of the head of the valve stem. As the activatingspring expands, the valve assembly shifts communicating the cold fluidopening in the valve stem with the cold fluid inlet opening into thehousing so that a mixture of cold and hot fluid is thereafter suppliedto the downstream control valve. When the temperature drops below theactivation temperature, the force of the second spring in the chamberwill act to close the cold fluid inlet opening, allowing only the hotfluid to pass therethrough.

The second spring is retained within the chamber by an end cap having anadjustable member extending therethrough. The tension member may includea threaded shaft having a moveable compression plate secured thereto.The plate engages one end of the spring within the chamber so that, byturning the adjustment member, the plate will be either urged tocompress the spring within the chamber to increase the force thereof ormoved away from the spring to reduce the force thereof against the headof the valve stem.

It is a primary object of the present invention to provide controllersfor regulating the flow of hot fluids in supply systems wherein eachcontroller utilizes a valve assembly which is moveable transversely withrespect to the flow passage through the controller so that the valve isoperable without regard to supply line pressures. Thus, the operation ofeach valve assembly is dependent solely upon the temperature of thefluid flowing therethrough.

It is yet another object of the present invention to provide flowcontrollers for regulating the flow of a hot fluid to an outlet so as toautomatically substantially terminate flow to the outlet in the eventthe temperature of the fluid is above a predetermined temperature and inwhich the valves may be manually reopened or automatically reopened,depending upon the specific environment in which they are to be used.

It is yet a further object of the present invention to providetemperature responsive fluid flow controllers having slidable valvesincorporated therewith which are activated by shaped memory alloysprings which transform from a martensitic to an austenitic state at apredetermined temperature to thereby regulate the flow of hot fluidthrough the controllers.

It is yet another object of the present invention to provide temperatureresponsive fluid flow controllers which may be operative as fluid mixerswhich regulate hot and cold fluid supply sources to mix the sources inthe event the hot fluid supply source reaches a temperature above apredetermined temperature so that thereafter, the cold fluid source ismixed with the hot fluid source, thereby maintaining operatingtemperatures at an appropriate or safe level.

It is a further object of the present invention to provide temperatureresponsive fluid flow controllers which are specifically adaptable foruse in both commercial and residential environments for controlling theflow of a hot fluid, such as water, downstream of a heating source sothat accidental contact with the water at temperatures above apredetermined temperature is substantially prevented as the controllerswill shut off such fluid flow until operating temperatures within thesupply system are decreased to a safe level.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is cross-sectional view taken through a first embodiment of afluid flow controller of the present invention showing a valve assemblyin a first open position relative to a fluid passageway through thecontroller housing;

FIG. 2 is a cross-sectional view similar to FIG. 1 showing the valveassembly in a second substantially closed position with respect to thefluid flow passageway through the controller housing;

FIG. 3 is an enlarged assembly view of the valve stem and cap of FIGS. 1and 2;

FIG. 4 is a reduced cross-sectional view of the housing of FIGS. 1 and 2showing the valve assembly stops;

FIG. 5 is a cross-sectional view of a second embodiment of the valveassembly of the present invention showing the valve assembly in an openposition relative to the fluid passageway through the controllerhousing;

FIG. 6 is a cross-sectional view similar to FIG. 5 showing the valvestem assembly in a substantially closed position relative to the fluidpassageway through the controller housing;

FIG. 7 is a cross-sectional view of another embodiment of the presentinvention wherein the controller housing and valve assembly are utilizedas a fluid mixer to mix a cold source of fluid with a hot source offluid at temperatures above a predetermined temperature with thecontroller being shown in this figure as allowing only the hot source offluid to pass therethrough; and

FIG. 8 is a view similar to FIG. 7 showing a mixing of hot and coldfluid sources through the controller housing.

DESCRIPTION OF THE PREFERRED EMBODIMENT

With continued reference to the drawings, a first embodiment oftemperature responsive fluid flow controller 20 is shown having ahousing 21, preferably molded of an ABS plastic material. The housingincludes an inlet opening 22 which communicates with an outlet opening23 by way of a fluid passageway 24. A bore 25 extends through thehousing in transverse, and preferably in perpendicular, relationshipwith respect to the passageway 24.

A valve assembly 28 is slidably mounted within the bore 25 so as to bemoveable from a first open position in which fluid may pass through thepassageway 24, as shown in FIG. 1, to a second generally closed positionwherein fluid flow is substantially terminated through the fluidpassageway 24, as shown in FIG. 2. The valve assembly includes a valvestem member 30 having a generally cylindrical base portion 31 with anannular groove 32 formed therein. A pair of generally opposing slots 33are cut into the side walls of the head portion so as to communicatewith the annular groove 32. A pair of guide stops 35 are molded with thehousing 21 and extend into the bore 25 adjacent the passageway 24. Thestops act as guides and as stops for controlling the movement of thevalve assembly within the bore 25. With reference to FIG. 3, the stopsextend within the slots 33 of the valve stem member and therebyeffectively prevent any rotation of the valve stem relative to thehousing 21. Further, the end walls 33' of each slot act as abutments forengaging the stops 35, see FIG. 4, when the valve assembly is shifted tothe second, or closed, position of FIG. 2.

The valve stem member 30 includes outer bifurcated barbed lockingelements 36 which are slightly tapered so as to be insertable through anopening 39 formed in a valve cap 40. The valve cap includes a generallycylindrical open chamber 41 through which the valve stem 30 extends. Acounter sunk opening 42 is also provided in the cap which communicateswith the open chamber 41 through the opening 39. When the bifurcatedbarbed end portions of the valve stem are inserted through the opening39, the barbs will lock on an annular flange 43 formed between theopening 39 and the opening 42.

The cap further includes an annular recess in the outer wall thereof inwhich an 0-ring 44 is selectively seated. The outermost end of the capincludes an outwardly extending flange 45 for purposes of limiting themovement of the valve assembly relative to the housing 21 as the flangewill abut the side wall of the housing when the valve assembly is movedto the rightmost position, as shown in FIG. 1, relative to the housing21.

In order to automatically shift the valve from the position shown inFIG. 1 to the position shown in FIG. 2 in the event that the fluidtemperature passing through the passageway 24 exceeds a predeterminedtemperature, a shaped memory alloy coil spring 46 is mounted within thechamber 41 surrounding the valve stem member 30. One end of the springabuts an end wall 47 of the chamber 41 and the opposite end abuts oneside of the stop members 35. The spring 46 is preferably formed of ashaped memory element alloy such as nickel, titanium ornickel/titanium/copper. The particular alloy or alloys from which thespring may be made may vary depending upon whether a gradual movement ofthe valve assembly from the open to the closed position is desired orwhether a snap-action of the valve position is desired. To develop asnap-action, some resistance must be provided between the valve assemblyand the housing. In the present embodiment, the O-ring 44 associatedwith the cap of the valve assembly and another O-ring 50 mounted in anannular groove in the base portion of the valve stem will resistmovement of the valve assembly. The resistance force must be overcome bythe shaped memory alloy coil spring 46 as the alloy increases intemperature, thereby changing from a martensitic state to an austeniticstate.

As the valve member is disposed transversely to the flow passage 24, thepressure within the passageway or elsewhere in the supply system willnot affect the operating characteristics of the valve assembly.Therefore, whenever the temperature of the fluid flowing therethroughheats the spring to the desired temperature wherein the change in stateoccurs, the valve will automatically move to a closed position, as shownin FIG. 2. When the preselected temperature which may vary from between110° to 135° F. is reached, for example, in a residential or commercialhot water supply system, the spring will rapidly expand andsimultaneously push against the stops 35 and the inner wall of the cap28, thereby driving the stem assembly to the left, as shown in FIG. 2.In the second or closed position, it should be noted that the annularface 52 of the base portion 31 is spaced slightly from a fully closedposition with respect to the fluid passageway and therefore, a limitedamount of fluid flow is allowed to pass through the passageway. Thisbleeding of the flow is desired so as to not adversely increasepressures between an upstream valve and the controller. In addition, thesteady passage of a trickle of fluid is desired so that when the fluiddecreases to a safe operating temperature, the fluid will continue tochange the temperature of the shaped memory alloy coil spring so thatthe spring pressure can be overcome to open the valve to the position ofFIG. 1.

In this respect, the embodiment of FIGS. 1 and 2 is directed to a manualresettable valve. Once the temperature of the fluid decreases to a safeoperating temperature, the valve assembly 28 may be manually pushed tothe right from the position in FIG. 2 to the position in FIG. 1, therebyopening the passageway 24. The movement will be limited by the lip orflange provided on the cap portion of the valve assembly. In the eventthat the fluid temperature remains at too high a temperature, the valvewill instantly close to the position of FIG. 2 under the influence ofthe spring 46.

With specific reference to FIGS. 5 and 6, a modified embodiment of thepresent invention is disclosed. The modified embodiment is substantiallyidentical to the previous embodiment with the exception that thecontroller is constructed to be automatically reset, or optionallymanually reset, to the open position.

The same numbers are utilized in the drawing figures as they relate tothe elements of the previous embodiment. In this embodiment, a secondspring 60 is mounted about the stem 30 within the annular recess 32. Oneend of the spring abuts an end wall 61 of the head portion of the valvestem and the other end abuts the stop members 35. The spring 60 isplaced in compression when the actuating spring 46 substantially closesthe valve, as shown in FIG. 6. As the spring 46 begins to cool, it willchange state, thereby allowing the force of the spring 60 to becomegreater, thus driving the piston assembly to the right, opening thepassageway 46, as shown in FIG. 5. The present embodiment may also beoperated manually by simply urging the piston assembly to the right toits fully open or first position.

With particular references to FIGS. 7 and 8, another embodiment of thepresent invention is shown in greater detail. In this embodiment, thecontroller 65 is designed to be placed upstream of an on/off valve forsupplying an outlet which may be, for example, a showerhead or bathtubor sink faucet. In this embodiment, the controller is designed to act asa fluid mixer which functions to maintain temperatures below apredetermined maximum by allowing a cold fluid to be mixed with a hotfluid. The controller includes a housing 70 having a hot fluid inlet 71and a cold fluid inlet 72 which communicate through the housing to anoutlet 73 positioned upstream of an on/off valve 74. The housing isgenerally cylindrical in configuration, having a closed end wall 75 andan open end 76 which is closed by a cap 77. A valve assembly 78 ismounted within a bore 79 the housing 70 and includes a generallycylindrical valve stem 80 which extends from a valve head 81 which isannular in configuration and which is sealed to prevent fluid flowbetween the head and the side walls of the housing by an O-ring 82. Thevalve stem includes a hot fluid inlet opening 83 and a cold fluid inletopening 84 which communicate through a secondary inlet opening 85through which fluid flows through the hollow stem to an elongated outletopening 86 which is in fluid communication with the outlet 73 of thehousing. A portion of the outer side wall 87 of the hollow valve stemfunctions as a valve seat, depending upon the position of the valve stemwithin the housing.

In a first position of the hollow valve stem, the hot fluid inletopening 83 of the valve assembly is open to the hot fluid inlet 71 ofthe housing with the cold fluid inlet 72 being closed by the side wallvalve seat 87. However, if the valve assembly is shifted to the right ofthe position shown in FIG. 10 to the position shown in FIG. 11, fluidflow is established through both the cold fluid and the hot fluid inlets72 and 71, respectively, to the outlet 73 of the controller. In order toregulate the temperature at which cold fluid is allowed to mix with thehot fluid, a first shaped memory alloy spring 90 is mounted within thehollow valve stem 80 and includes one end for abutting the closed endwall 75 of the housing and a second end which abuts the head 81 of thevalve assembly. The material from which the spring is made may be anyalloy which changes from a martensitic state at temperatures below apreselected temperature to an austenitic state at temperatures above thepreselected temperature. The temperature may be selected, for instance,between 110° and 135° F. The spring 90 applies pressure to move thevalve stem away from the closed end wall 75. This movement is offset bya secondary coil spring 92 mounted within the bore 79 in an area of achamber formed between the head portion 81 of the valve stem and the cap77 of the housing. Spring 92 may be any conventional metallic springwhich applies a fairly constant biasing force toward the left or closedend wall 75 of the housing. In order to adjust the amount of biasingforce of the spring 92, a pressure plate 93 is mounted to a threadedshaft 94 of an adjustment screw 95. By adjusting the screw, the pressureplate 93 may be urged against one end of the spring 92 to increase theamount of biasing force. By rotating the screw in the oppositedirection, the force on the spring may be decreased.

In the use of the controller 65, when the downstream valve 74 is turnedon to allow fluid flow, the controller 70 will be in the position shownin FIG. 7, allowing substantially all flow to come from the hot fluidsource. As the temperature of the hot fluid increases as it is receivedfrom a source of hot fluid supply, the temperature of the spring 90 willincrease to the point where the material changes state and suddenlyexpands against the pressure of the opposing spring 92 toward theposition shown in FIG. 8. In this embodiment, the particular alloyutilized for the spring 90 may allow a slow expansion over a temperaturerange so that the valve seat 87 increasingly opens the cold fluid inlet72 into the housing, thereby adjusting the temperature of the fluidpassing through the controller to the outlet 73. When the downstreamvalve 74 is turned off or the temperature through the controller dropsbelow the predetermined range, the spring 92 will bias the valveassembly back to the position shown at FIG. 7.

The foregoing description of the preferred embodiment of the inventionhas been presented to illustrate the principles of the invention and notto limit the invention to the particular embodiment illustrated. It isintended that the scope of the invention be defined by all of theembodiments encompassed within the following claims and theirequivalents.

What is claimed is:
 1. A temperature responsive fluid flow controllerfor regulating fluid flow to an outlet so as to regulate flow attemperatures above a predetermined temperature, the controllercomprising,a housing having a fluid inlet and a fluid outlet, a fluidpassageway extending between said inlet and said outlet, a boreextending transversely to and communicating with said fluid passageway,a valve assembly slidably disposed within said bore, said valve assemblyincluding opposite ends which are spaced in non-liquid communication onopposite sides of said fluid passageway and a secondary fluid passagewaydefined through said valve assembly intermediate and spaced from saidopposite ends, said valve assembly being moveable between a firstposition wherein said valve assembly is positioned within said bore suchthat said secondary fluid passage is in open communication with saidfluid passageway of said housing and thereby permits flow through saidfluid passageway to a second position wherein said valve assembly ispositioned within said bore such that said secondary passageway issubstantially closed relative to said fluid passageway of said housingand thereby only limited fluid flow is permitted through said fluidpassageway, and a first shaped memory alloy spring means mounted withinsaid bore, said first spring means communicating with said fluidpassageway so as to be in heat exchange relationship to the fluidpassing therethrough whereby when the fluid temperature increases tosaid predetermined temperature, said first spring means changes state tothereby expand and shift said valve assembly from said first portion tosaid second portion.
 2. The temperature responsive fluid flow controllerof claim 1 including a second spring means mounted within said bore soas to apply an opposing force relative to said first spring whereby saidsecond spring means automatically shifts said valve assembly from saidsecond position to said first position when the temperature of saidfirst spring means falls below said predetermined temperature.
 3. Thetemperature responsive fluid flow controller of claim 1 wherein saidbore extends completely through said housing, said valve assemblyincluding a valve stem having a base portion and a cap portion of a sizeto be cooperatively received within said bore, seal means for sealingeach of said base portion and said cap portion to side walls definingsaid bore through said housing on opposite sides of said fluidpassageway, said first spring means being mounted about said valve stem.4. A temperature responsive fluid flow controller for regulating fluidflow to an outlet so as to regulate flow at temperatures above apredetermined temperature, the controller comprising,a housing having afluid inlet and a fluid outlet, a fluid passageway extending betweensaid inlet and said outlet, a bore extending transversely to said fluidpassageway and completely through said housing, a valve assemblyslidably disposed within said bore and moveable between a first positionwherein said valve assembly permits flow through said fluid passagewayto a second position wherein said valve assembly at least partiallyregulates fluid flow through said fluid passageway, said valve assemblyincluding a valve stem having a base portion and a cap portion of a sizeto be cooperatively received within said bore, seal means for sealingeach of said base portion and said cap portion to side walls definingsaid bore through said housing on opposite sides of said fluidpassageway, a first shaped memory alloy spring means mounted within saidbore, said first spring means being mounted about said valve stem, saidfirst spring means communicating with said fluid passageway so as to bein heat exchange relationship to the fluid passing therethrough wherebywhen the fluid temperature increases to said predetermined temperature,said first spring means changes state to thereby expand and shift saidvalve assembly from said first portion to said second position, and saidbase portion of said valve assembly including an annular recesssurrounding a portion of said valve stem, said cap portion including acylindrical chamber through which said valve stem extends and in whichsaid first spring means is mounted, stop means extending from saidhousing into said annular recess in said base portion of said valveassembly adjacent said fluid flow passageway, and a first end of saidfirst spring means engaging said cap portion and said second portionengaging said stop means.
 5. The temperature responsive fluid flowcontroller of claim 4 including slots formed in said base portion ofsaid valve assembly extending from adjacent said fluid passageway intosaid annular recess, said stop means being slidably received within saidslots.
 6. The temperature responsive fluid flow controller of claim 5including a second spring means mounted within said annular recess insaid base portion of said valve stem and having a first portion engagingsaid stop means and a second portion engaging said valve stem, saidsecond spring means being mounted to oppose the force created by saidfirst spring means whereby said second spring means will urge said valveassembly from said second position to said first position when thetemperatures of said first spring means fall below said predeterminedtemperature.
 7. The temperature responsive fluid flow controller ofclaim 4 in which said cap portion includes an outer flange which extendsoutwardly relative to said bore, said flange being engageable with saidhousing to limit the relative movement of said cap portion of said valveassembly inwardly of said bore in said housing.
 8. The temperatureresponsive fluid flow controller of claim 4 in which said base portionof said valve assembly extends outwardly of said housing when said valveassembly is in said second position.
 9. The temperature responsive fluidflow controller of claim 4 where said valve assembly permits limitedfluid flow through said passageway when in said second position.
 10. Atemperature responsive fluid flow controller for regulating fluid flowto an outlet so as to regulate flow at temperatures above apredetermined temperature, the controller comprising,a housing having afluid inlet and a fluid outlet, a fluid passageway extending betweensaid inlet and said outlet, a bore extending transversely to said fluidpassageway and completely through said housing, a valve assemblyslidably disposed within said bore and moveable between a first positionwherein said valve assembly permits flow through said fluid passagewayto a second position wherein said valve assembly at least partiallyregulates fluid flow through said fluid passageway, a first shapedmemory alloy spring means mounted within said bore, said first springmeans communicating with said fluid passageway so as to be in heatexchange relationship to the fluid passing therethrough whereby when thefluid temperature increases to said predetermined temperature, saidfirst spring means changes state to thereby expand and shift said valveassembly from said first portion to said second position, and said valveassembly including a valve stem having a base portion and a cap portionof a size to be cooperatively received within said bore, seal means forsealing each of said base portion and said cap portion to side wallsdefining said bore through said housing on opposite sides of said fluidpassageway, said first spring means being mounted about said valve stem,said valve stem including a bifurcated end portion, said cap portionincluding an opening through which said bifurcated end portions extends,and said bifurcated end portion including barbs for engaging a recess insaid cap portion to thereby retain said cap portion to said valve stem.11. The temperature responsive fluid flow controller of claim 10including a second spring means mounted within said bore so as to applyan opposing force relative to said first spring whereby said secondspring means automatically shifts said valve assembly from said secondposition to said first position when the temperature of said firstspring means falls below said predetermined temperature.